Astragaloside IV remodels gastric inflammation-cancer transformation by modulating the CXCL5-CXCR2 axis-mediated epithelial-mesenchymal transition.

[BACKGROUND] Chronic atrophic gastritis (CAG) is a pivotal intermediate stage in the progression from chronic gastritis to gastric cancer (GC), and it poses a serious threat to human health. Astragaloside IV (AS-IV), a major bioactive compound derived from the traditional Chinese medicinal herb Astragalus membranaceus, has demonstrated therapeutic potential against both CAG and GC. Nevertheless, the exact biological mechanisms underlying these effects remain unclear.

[PURPOSE] This research was conducted to assess the effects of AS-IV on gastric inflammation-cancer transformation and to elucidate its underlying mechanisms.

[METHODS] We collected gastric tissue and blood samples from healthy individuals, patients with CAG, and patients with GC. The levels of CXCL5 and CXCR2 were quantified using ELISA and immunohistochemistry. To establish in vitro models of CAG and GC, we employed the GES-1 and MKN45 cell lines. Experimental interventions included lentiviral-mediated CXCL5 knockdown (shCXCL5-KD), CXCR2 knockdown (shCXCR2-KD), CXCL5 overexpression (shCXCL5-OE), and treatment with AS-IV. Cellular responses were evaluated using multiple assays: Western blotting to assess protein expression, quantitative real-time polymerase chain reaction (RT-qPCR) to measure mRNA levels, CCK-8 for cell viability, ELISA for cytokine quantification, and wound healing, along with Transwell assays to assess cell migration. For in vivo validation, CAG models were established in Sprague-Dawley (SD) rats and GC models in BALB/c nude mice, with AS-IV administered according to the designated experimental groups. Systematic evaluations were performed using multiple techniques: hematoxylin and eosin (H&E) staining to assess histopathological changes, immunohistochemistry to determine protein localization, western blotting to analyze signaling pathways, and ELISA to quantify systemic cytokine levels. Together, these approaches enabled a comprehensive, multi-level analysis of the therapeutic mechanisms at both the cellular and whole-organism levels.

[RESULTS] Our findings showed that CXCL5 and CXCR2 expressions were markedly elevated in both clinical samples from patients with CAG and GC and in corresponding experimental models, with their expression positively correlating with disease severity. Mechanistically, we demonstrated that the CXCL5/CXCR2 signaling axis drives the progression from gastric inflammation to cancer through CXCR2-dependent activation of the ERK/Elk-1 pathway, which in turn induces epithelial-mesenchymal transition (EMT). Notably, AS-IV effectively mitigated this pathological process by selectively disrupting the CXCL5-CXCR2 interaction, modulating downstream signaling pathways, and eventually suppressing the inflammation-to-cancer transition.

[CONCLUSION] Our study identifies ERK/Elk-1-dependent EMT, driven by activation of the CXCL5/CXCR2 signaling axis, as a key pathogenic mechanism underlying the progression from gastric inflammation to cancer. Importantly, AS-IV, a bioactive compound derived from the traditional medicinal herb Astragalus membranaceus, effectively disrupts this cascade, demonstrating therapeutic potential against both CAG and GC by preventing the malignant transformation of chronic inflammation into carcinoma.